US crude ends near $99 in whipsaw session; stockpiles weigh

U.S. crude oil futures tumbled nearly $1 on Thursday, as builds in domestic stockpiles and a strong U.S. dollar outweighed worries over the possible impact of tougher U.S. sanctions on Russia.

In the latest sign of mounting tensions over Moscow's annexation of Crimea, the U.S. expanded its sanctions to 20 more prominent Russians, including allies of Russian President Vladimir Putin. Russia retaliated with its own sanctions against 9 U.S. officials and lawmakers.

Comments from U.S. Federal Reserve Chair Janet Yellen on Wednesday indicated the U.S. central bank could end its stimulus program this autumn and then might raise interest rates sooner than expected, sending the U.S. dollar higher against other major currencies.

This pressured oil and commodities priced in the dollar, even as economic data out of the U.S. was mixed. Initial state jobless claims rising 5,000 last week while factory activity in the Mid-Atlantic region accelerated in March.

Gasoline inventories at Europe's Amsterdam-Rotterdam-Antwerp (ARA) storage hub rose near-six-year highs last week indicating ample supply and exacerbating data from the U.S. that showed domestic crude inventories rose sharply for a second week in a row.

U.S. crude for April delivery, which will expire at the settlement on Thursday, fell 94 cents to settle at $99.43 per barrel. Earlier in the session, the contract fell as low as $99.08. Brent rose 60 cents to over $106 a barrel.